Typically the ideal location for first detecting a leak is adjacent to the source of the leak for the purpose of not only stopping the leaks as soon as possible to minimize damage, but to pinpoint the actual source of the leak, however, usually the leak source is in an difficult to access location or area, thus placement of an automated leak detection apparatus in its ideal location will hasten the timeliness of a useful perceptible output from the leak detection apparatus to minimize damage to either or both the machine that may be malfunctioning via leaking or surrounding structure affected by the leak. However, as a practical matter, having an automated leak detection apparatus everywhere a leak may occur is not realistic due to the multitude of potential leak locations causing undue complication and cost.
Wherein normally without the presence of any type of leak detection apparatus, a small liquid leakage from a machine, say for instance hidden underneath a large heavy ice making machine (that is rarely moved) that has a low volumetric flow rate leak or in other words a seeping leak can cause significant damage to the machine and/or surrounding adjacent structure prior to being detected. Unfortunately, the ice machine will continue to work perfectly during its small leakage phase thus not alerting a user to the presence of the slight leakage condition, at least until the surrounding structure suffers significant damage, wherein the leak would more likely be detected.
Thus, this situation can continue for quite some time until extensive damage has occurred in the hidden machine portions and/or support structure, wherein at some later in time point the structural damage eventually becomes obvious, wherein the structural damage from the liquid seepage is more excessive than it should be. Thus, the result is that the support structure suffers additional damage that is hidden from view in addition to the leaked fluid, typically water or even worse a fluid that is toxic or chemical in nature that could risk further safety, electrical risk, or environmental harm. Unfortunately, water damage can most likely occur one the office or home is vacant wherein a frozen pipe can be burst shutoff valves can fail to say toilet tanks or for instance refrigerator ice makers can have line ruptures in addition to dishwashers, and items such as broken hoses to washing machines. The typical damage would include damage to wallboard, wallpaper, paint, electrical fixtures and wiring, carpeting and padding, vinyl flooring, subflooring, or building structure, plus furniture and other household items. In addition, items such as financial records, photos, and other irreplaceable items can be destroyed beyond retrieval or repair. Further, later forming issues can include hazardous molds and the like that will require even more costly and difficult cleanups.
Thus, the key issues for the leak detection apparatus involve, small space or size requirements for the apparatus, as the specific placement location for the apparatus may be in a confined area with difficult accessibility, a further issue in the leak detection apparatus is the sensitivity of generating a perceptible output from a very low liquid leakage flow rate, usually in the range of about one-third (⅓) of a gallon per minute to detect a leak prior to a significant damage occurring, i.e. catching the leak as soon as possible. Another issue for the leak detection apparatus is to ideally have a single leak detection apparatus able to cover a multitude of potential leak points for ease of installation and to reduce cost, and in addition for the leak detection apparatus to automatically shutdown the root source of the leakage based upon the detection of leakage to minimize damage either to machines, equipment, or the surrounding structure or environment from leakage damage.
Looking at the prior art in this area, in U.S. Pat. No. 7,900,650 to Wilson disclosed is a system that provides for the remote control shutoff of the main water supply to a structure in an unattended manner. The Wilson system comprises a solenoid activated shutoff valve typically mounted immediately downstream of a main water shutoff valve and a locking enclosure containing a remote control switch and audible alarm unit. A manual bypass valve in Wilson is provided as an override should it be required. Also in Wilson, because the system requires electricity to operate, a general power failure will automatically shut off of the water supply. Further, activation of the Wilson system is accomplished using a remote control to control the system from a distance. Note that there is no teaching of a flow meter in a bypass line disclosed in Wilson in conjunction with the solenoid activated shutoff valve, a bypass line is taught, however, only with a manual valve. Wilson does not also teach the automated shutting off of the water supply in the event of a leak occurring when there is no one around the house or water system, as Wilson requires the manual selectively shutting off of the water system, suggesting that the water system be completely shut off when the homeowner is absent, however, in this case the homeowner could just manually shut off their main water valve without the Wilson system. Also when a homeowner is absent, Wilson ignores the fact that a hot water heater needs a continuous feed of water even without use, unless Wilson advocates shutting down the hot water heater also, which was not disclosed.
Continuing in the prior art, in U.S. Pat. No. 6,945,274 to Davis being similar to Wilson, wherein Davis discloses a modular water supply shut off and by manual valve pass system that can be installed in a standard water supply line and used to prevent water flow through the supply line except when the system is activated. The system in Davis includes a modular unit having main fluid flow line provided with a remotely actuated valve and the manual bypass fluid flow line provided with a manually operated valve for cases of when the remotely actuated valve fails. The system in Davis also has a control unit that includes a timing mechanism that be operated to actuate the remotely actuated valve and allow water to flow through the main fluid flow line for a manually selected period of time determined by the timing mechanism. A momentary switch in Davis is coupled to the control unit and used to actuate the timing mechanism. Thus, Davis is design to facilitate the water main valve to be “on” or open for the selected amount of time and then to automatically close the main valve when the selected time has elapsed, say for instance in a vacation home, also included is a reset momentary switch which can re-start the timer. Davis does not teach any form of leak detection or water system automatic shut off in the event of a water system leak, as there is no measure of flow rate with a flow meter.
Further, in the prior art looking at U.S. Pat. No. 7,574,896 to Cooper disclosed is a leak detection apparatus for detecting and controlling a leak in a pressurized piping system, which comprises: control logic; both of one and only one flow detector in communication with said logic, and one and only one pressure detector in communication with said logic; and a control valve in communication with said logic; wherein at least one of the following additional features is also provided: the control logic, both of one and only one flow detector and one and only one pressure detector, and the control valve are in close proximity to one another; and the control valve has a baseline condition of being shut off. In Cooper, the pressure detector works via detecting pressure degradation and/or flow rate increase, however, pressure detection to monitor low leakage situations would be problematic, as with slow leaks, pressure drop may not even occur as the municipal water supply will maintain a constant feed pressure of water into the system unless the flow rate is excessively high causing a water system pressure drop, the only instance wherein system pressure drops would detect small leakage is when the system does not have a pressure water or liquid feed, such as a closed off system, however, the teaching is for a municipal constant water pressure feed system, see column 6, lines 10-15, thus water pressure sensing would only detect relatively high flow rates. In operation in Cooper, the flow detector is used for sensing user demand, in which case there is user demand, then the main valve remains open until user demand ceases, at which time flow rate detection and pressure drop detection would activate closing of the main valve, although teaching of how user demand is really sensed is not present-however, it would typically involve some form of electronic sensor at each water use appliance, which would be complicated and costly, Cooper does mention using the timer for a time window in which user demand is assumed thus negating when flow or pressure sensing would activate closing the main valve, however, this could facilitate a leak being allowed to proceed (i.e. no main valve shut off) if the user demand time window is longer. Note that the flow detector in Cooper must be sized and configured to handle the full flow rate of the system, which would limit the low flow rate detection limit, especially in larger flow rate systems, as the flow detector is not in a bypass loop-but is in the main flow loop.
Next, in the prior art, in looking at U.S. Pat. No. 5,415,033 to Maresca, Jr., et al. disclosed is a apparatus for detection of leaks in pressurized pipelines which utilizes a large pressure vessel and a small measurement vessel. The measurement vessel in Maresca, Jr. magnifies level changes during leak detection tests due to volume change amplification from the small measurement vessel, wherein the apparatus is connected to a pipeline through the measurement vessel. The entire system in Maresca Jr. can be filled with liquid from the pipeline by opening a valve between the measurement and pressure vessels. Leak detection tests in Maresca Jr. are conducted by measuring changes in volume with the measurement vessel over time while the pressure over the liquid in the pressure vessel and measurement vessel is maintained approximately constant and during tests, liquid communication between the measurement vessel and pressure vessel is prevented by closing the valve between them, but vapor communication between the vessels is permitted, thus measurement by volume is done not by pressure-wherein the pressure is maintained at a constant level by large pressure vessel to eliminate pressure effects on the volume measurement due to the typical hydrocarbon having high sensitivity to environmental conditions that cause variance in vapor pressure of the liquid in the system being measured for leakage. Note that there is no need for a flow meter in Maresca Jr., which would be considered undesirable due to the low leakage flow rates required to be detected being around 0.1 gallon per hour.
Further, in the prior art in U.S. Pat. No. 7,849,890 to Jones disclosed is an assembly, comprising: a sealed housing; at least one moisture-sensitive component disposed of within the sealed housing. Jones is designed for electronic equipment that is disposed within the sealed housing for protection from the elements, wherein it is desired to detect a buildup of moisture within the housing. The housing in Jones has a first sensor element operable to generate a first signal in response to moisture in a first state being present at a first predetermined level within the sealed housing; also a first valve element coupled to the housing and, in response to the first signal, operable to enable at least a portion of the moisture to exit the housing at the first valve element. Further in Jones, a second sensor element is operable to generate a second signal in response to moisture in a second state being present at a second predetermined level within the sealed housing; a third sensor element operable to sense that a pressure outside the housing is less than a pressure within the housing; and a second valve element coupled to the housing. In response to the second signal in Jones, it is operable to enable at least a portion of the moisture to exit the sealed housing at the second valve element if and only if the pressure level inside the sealed housing is greater than a pressure level outside the sealed housing. Note that in Jones there is no flow meter, as Jones basically utilizes a float switch (moisture-sensitive component) and valve that senses a certain level of an amount of static moisture accumulation in the housing-sends a signal from the switch and the valve facilitates the moisture level buildup to exit the housing.
There remains a need for a fluid leak detection and shutdown apparatus that is simple to install, is self contained in not needing remotely mounted sensors, utilizes a flow switch bypass loop-allowing for a smaller (lower flow rate) and more accurate flow sensor for lower flow rates that is less expensive, and a time delay to main valve actuation to the closed position thus accommodating normal system low flow but temporary flow items such as refrigerator ice makers, evaporative coolers, hot water heater refills, and the like, such as to not cause unnecessary shut-offs of the main valve actuation. A single fluid leak detection and shutdown apparatus should be able to detect any leak within a system from a central inlet location within the system and after the proper conditions have been satisfied automatically shut down the main valve actuation to the system to stop the leakage and thereby the subsequent damage to the equipment and environment.